Background: High tibial osteotomy is an established and helpful treatment for unicompartmental osteoarthritis associated with varus deformity. However, asupratubercle high tibial osteotomy leads to a decrease in patellar height making the technique not suitable in the case of concomitant patella Baja. Moreover, this kind of osteotomy can change in situ forces at the patellofemoral joint and the lateral patellar tilt. To widen the indication of high tibial osteotomy was proposed a biplane opening wedge high tibial osteotomy with a distal tuberosity osteotomy (B-OWHTO). Objective: To assess the clinical and radiological outcome of biplane open wedge high tibial osteotomy in the treatment of medially arthritic varus knees. Patient and Methods: Twenty varus knees (20) patients, with MCOA, were operated upon from 2019 to 2020 at Al-Azhar University Hospital (Assiut). They all had Medially Opening Wedge High Tibial (MOWHTO) using the biplanar technique and fixed by locking plates. We compared the data fetched preoperatively (at day 0 = D0) with data one year or more after surgery with a mean of 14.5 months (at year 1=Y1). The mean age was 49.39 ± 8.15 years old, 13 were females, while others were males. Eleven were right knees, and 7 were left. Types of occupation were; 9 employed, 7 unemployed. Sixteen were no sportive, and 2 were recreational athletes. Seven patients were normal weight, while 11 were overweight. Two patients were diabetic, and 2 were perceived as treated HCV infection. According to the MCOA K-L scale; 5 were grade 3, 9 were grade 2 and 4 were grade 1. Results: The mean western Ontario and Macmaster universities osteoarthritis index (WOMAC), value was 51.44 ± 26.8 and then dropped to 24. 39 ± 17.41. The difference was statistically significant (p-value was <0.001). The mean Cincinnati score was 40.36 ± 19.28 at D0, then 81.88 ± 14.45 at Y1. The rising pattern from D0 to Y1 was significant statistically (p-value was <0.001). For radiological results, the mean amount of correction was 10.56º ± 2.97º. The mean TS for the18 patients was 10.78º ± 2.92º and changed to 10.49º ± 2.51º, and this was statistically insignificant. Regarding the patellar height (PH), there was a statistically significant decreasing tendency from a mean of 1.02 ± 0.16 to 0.97 ± 0.15. LPT showed a statistically significant decrease, although quite small, from 10.48 º ± 6.18 º to 9.43º ± 4.27º. MOWHTO using biplanar technique and fixed by the locking plate without BG filling was a very efficient modality of treatment for adult patients suffering from medially arthritic varus knees in terms of clinical and radiological aspects. Conclusion: Medial Open Wedge High Tibial Osteotomy (MOWHTO) using biplanar technique and fixed by the locked plate without bone graft filling was a very efficient modality of treatment for adult patients suffering from medially arthritic varus knees in terms of clinical and radiological aspects.